Phrase guide
Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.
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noun
A subatomic particle with an unusually long lifetime (7.2 × 10−21 s) and a large mass (approx. 3.097 GeV/c2); a bound state of a charm quark and an anti-charm quark (the most common form of charmonium).
Definition source: English Wiktionary via Wiktextract
Usage: particle
Topics: natural-sciences, physical-sciences, physics
No example sentence was provided for this meaning.
Synonyms: J/psi meson, psion
Antonyms: none provided
History
A compound of J, ψ (ps) (psi), and particle. The particle was discovered independently in 1974 by two research groups, leading to the "November Revolution" in particle physics. * The group led by Samuel Ting at Brookhaven National Laboratory proposed the name J, reputedly because the shape of the Chinese character for Ting (丁) resembles a J, though Ting also cited the symbol for electromagnetic current, j_μ(x), as a reason. * The group led by Burton Richter at SLAC proposed the name ψ (psi). Richter initially preferred "SP" (for the SPEAR accelerator), but chose "psi" as it contained "SP" in reverse order and was the only remaining Greek letter deemed suitable; coincidently, the particle's decay pattern in spark chambers resembled the letter ψ. The compromise name J/ψ was adopted to acknowledge both discoveries.
Across languages
10 source translations are retained for this English entry.
